Morphology-Controlled Long-Range Photogenerated Charge Carrier Transfer Pathway for Enhanced Photocatalytic Hydrogen Production.

Abstract

Achieving precise control over the construction of efficient charge transport channels through self-assembly engineering represents a highly effective strategy for the synthesis of organic supramolecular photocatalysts. Herein, tetragonal zinc meso-5,10,15,20-tetra(4-pyridyl) porphyrin (ZnTPyP) nanorods (T-ZnTPyPs) and hexagonal ZnTPyP nanowires (H-ZnTPyPs) were synthesized by varying the assembly temperature. H-ZnTPyPs demonstrated a photocatalytic hydrogen production rate (183 mmol/g/h) that was 14.62 times greater than that of T-ZnTPyP (13 mmol/g/h). This significantly enhanced activity is primarily attributed to the distinct and well-defined molecular arrangements of H-ZnTPyPs, which support continuous linear long-range electron transfer pathways through effective π-π stacking. Conversely, the heat manipulation used in the synthesis of T-ZnTPyPs limits the participation of water molecules in the crystalline stacking arrangements, leading to lattice distortions that disrupt the π-π stacking interactions and significantly impede long-range electron transfer pathways. This research presents a novel strategy for modulating π-π stacking to optimize charge transport in supramolecular photocatalysts.